docs: def get_tunnel_context(self, context_id, **kwargs):
          """Retrieves the network tunnel context instance.
  
          :param int context_id: The id-value representing the context instance.
          :return dict: Mapping of properties for the tunnel context.
          :raise SoftLayerAPIError: If a context cannot be found.
          """
          _filter = utils.NestedDict(kwargs.get('filter') or {})
          _filter['networkTunnelContexts']['id'] = utils.query_filter(context_id)
  
          kwargs['filter'] = _filter.to_dict()
          contexts = self.account.getNetworkTunnelContexts(**kwargs)
          if len(contexts) == 0:
              raise SoftLayerAPIError('SoftLayer_Exception_ObjectNotFound',
                                      'Unable to find object with id of \'{}\''
                                      .format(context_id))
          return contexts[0]